Prediction of long term filtration by coupled gel layer and pore transport model for salt removal using mixed matrix hollow fiber ultrafiltration membrane

Abstract

Characterization and performance of lanthanum cobalt oxide nanoparticle doped hollow fiber ultrafiltration membrane are reported in this paper. Nanoparticles (1 wt%) having zeta potential −30 mV at pH 7 imparted high surface charge (surface potential ~19 mV) to the hollow fibers. At this composition, the membrane became more hydrophilic with contact angle reduced to 520 from 570 corresponding to without nanoparticles. Permeability of hollow fiber with 1 wt% nanoparticles increased by 40% compared to that without nanoparticle. At this composition, the membrane molecular weight cut off was 4000 Da (with average pore diameter 34 nm) belonging to ultrafiltration range. Rejection of sodium chloride was 47% in 1000 mg/l synthetic solution at transmembrane pressure drop 69 kPa and cross flow rate 20 l/h. Performance of developed hollow fiber membrane was also tested using actual seawater with a rejection of 40% total dissolved solids at 138 kPa at 20 l/h with 15 l/m2h permeate flux. A combined gel polarization and pore flow model was used to quantify the long term flux decline and salt concentration in the permeate as function of time.